We're one step closer to building artificial cells. Synthetic biologists have found a new way to assemble "genetic circuits," components that perform logical operations in living cells. This breakthrough could facilitate the development of artificial cells designed to solve problems in medicine, energy, and the environment.

This new technique, which was developed by Boston University biomedical engineers Ahmad S. Khalil and James J. Collins, could equip synthetic biologists with an entirely new set of genetic components for them to do their work — a development that could significantly increase the size and complexity of genetic circuits that can be built.

In other words, the potential diversity and sophistication of artificial life just got a whole lot bigger.

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A report in Genetic Engineering & Biotechnology News tells us how it was done:

Recent advances in designing proteins that bind to DNA gave the researchers the boost they needed to start building a new library of transcription factors. In many transcription factors, the DNA-binding section consists of zinc finger proteins, which target different DNA sequences depending on their structure. The researchers based their new zinc finger designs on the structure of a naturally occurring zinc finger protein. "By modifying specific amino acids within that zinc finger, you can get them to bind with new target sequences," Dr. [Timothy] Lu says.

The researchers attached the new zinc fingers to existing activator segments, allowing them to create many combinations of varying strength and specificity. They also designed transcription factors that work together, so that a gene can only be turned on if the factors bind each other.

Such transcription factors should make it easier for synthetic biologists to design circuits to perform tasks such as sensing a cell's environmental conditions. The researchers built some simple circuits in yeast, but they plan to develop more complex circuits in future studies. "We didn't build a massive 10- or 15-transcription factor circuit, but that's something that we're definitely planning to do down the road," Dr. Lu says. "We want to see how far we can scale the type of circuits we can build out of this framework."

The researchers are also hoping to apply their new transcription factors to human cells.